JPH0931507A - Method for tracking charged material in blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a tracking method of a charged material in a blast furnace which can further surely execute the estimation of remained iron quantity and remained slag quantity in the blast furnace at each iron tapping. SOLUTION: At the time of charging raw material into the blast furnace, the charged material level just after charging is measured at each completing one lot of charging and the whole vol. (actual vol. value) of the charged material existing in the furnace is obtd. from this value. Then, after obtaining a theoretical vol. value of the charged material existing in the furnace at this time point, 'actual col. value- theoretical vol. value' is calculated. In the case of being negative to this value, it is estimated that the charged material existing in the furnace is made to discharge out of the furnace in order in each charging lot from the most previous charged one by the quantity until the above value converts to the positive value. Further, at the time of obtaining the above theoretical vol., a vol. conversion factor in the solid-liquid mixing state and a vol. conversion factor in the solid state are arranged, and the vol. conversion is executed based on the vol. conversion factor in the solid-liquid mixing state from the most previous charged one in the charging lot existing in the furnace in order and accumulated. The vol. conversion is executed and accumulated based on the vol. conversion factor in the solid state at the following time since the accumulated value exceeds a prescribed value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for tracking the contents of a blast furnace interior, which enables highly accurate control of the amount of residual pig iron and the amount of residual slag.

[0002]

2. Description of the Related Art In blast furnace operation, since pig iron and slag generated in the furnace are successively accumulated in the hearth, a slag mouth or a tap hole is opened at an appropriate time and discharged to the outside of the furnace. The work to do is repeated. However, since the slag accumulated on the pig iron in the hearth has a much higher viscosity than that of pig iron, it is often the case that the slag is not completely discharged even by the discharging work. When the operation of closing the slag port or the tap hole and continuing the reinforcement with the slag remaining in the furnace in this way is repeated, the slag level of the hearth gradually rises, and This will cause the reactor to be in poor condition such as hanging, and will eventually be forced to reduce production. Therefore, it is necessary to discharge the slag accumulated in the hearth of the blast furnace as completely as possible each time the slag is discharged, and be careful not to raise the slag level in the hearth too much.

On the other hand, in recent years, along with the increase in size and efficiency of blast furnaces, a method of performing slag by using only the taphole has become widespread, but as described above, the kinematic viscosity of the slag is The kinematic viscosity of pig iron is very high (about 100 times higher), so the slag method using only the tap hole tends to cause insufficient discharge of molten slag, so pay special attention to the discharge. There is a need.

[0004] Therefore, conventionally, the "amount of tapped metal and the amount of slag (measured by a load cell type weighing machine or the like)" and "the calculated amount of tapped metal and the amount of slag" are used to determine the inside of the blast furnace. The operation has been carried out while estimating the amount of residual pig iron and the amount of residual slag.

According to this method, a predetermined number of "charges", which are the minimum units selected in view of operation management of the blast furnace, are generally called in a blast furnace (generally called a batch or an aggregate of batches). Will be referred to as "charge" hereinafter) ", and every time one charge is loaded into the furnace," 1 charge was loaded into the furnace means that it was loaded into the blast furnace. The oldest existing charge (the one in the lowest layer of the furnace) was discharged to the outside of the furnace. "" The calculated amount of tapping and the calculation for the oldest charge The amount of slag and the amount of slag in the furnace were estimated from the "amount of slag" and "the amount of slag and the amount of slag.
In other words, in the past, the amount of residual pig iron and amount of residual iron in the furnace was estimated based on the premise that "one charge is always discharged if one charge is charged".

However, in reality, the scale reduction operation (see FIG.
As shown in Fig. 3, when the operation is performed with the amount of furnace interior material reduced compared to that during normal operation) or when there is a break in the air, the charging into the furnace is stopped or the charging interval is lengthened. There is a case where the level of the charge inside is lowered, and therefore the above-mentioned assumption that "there is always a predetermined number of charges in the furnace" is not suitable for the actual situation. Further, the same volume of charge is not always charged every time, and in some cases, as shown in FIG. 2, for example, the discharged amount (A) is smaller than the charged amount (D). That is, computationally, tea present in the bottom of the furnace - May have for example _^1/2 di volumes also "1 Cha - - volume of di is Cha charged to new furnace di instrumentation "One charge was discharged when it was turned on" means that the mass balance (difference between the charged volume and the discharged volume) in the furnace was not faithfully reproduced. Therefore, it is considered that controlling the discharge of molten pig iron and slag based on this concept is one of the causes of instability of blast furnace operation and reactor condition.

Therefore, the object of the present invention is to make it possible to more accurately estimate the amount of residual iron and the amount of residual slag in the blast furnace, which is carried out for each tapping, and to make it possible to more accurately estimate the contents of the furnace interior. It was to establish a tracking method.

[0008]

The present invention has been completed based on the results of research conducted by the inventors of the present invention, etc., which have been earnestly conducted to achieve the above-mentioned object. When the raw material is charged into the blast furnace, the "level of the charged material" immediately after the charging is measured every time the charging of the minimum unit for management is completed, and from that level into the furnace. After determining the total volume (actual volume) of the existing charge and the theoretical volume of the charge existing in the furnace at that time, the difference between the actual volume and the theoretical volume (actual volume) Volume value-Theoretical volume value)
If this value is negative, the charges existing in the furnace are sequentially discharged from the oldest one by the amount until the above value changes to positive, from the oldest one to the smallest unit. By adopting this method, it is possible to operate the blast furnace accurately and stably. ”
`` In the above method, when calculating the theoretical volume of the charge existing in the furnace, the volume conversion coefficient in the solid-liquid mixed state and the volume conversion coefficient in the solid state were set, and the minimum control unit existing in the furnace was set. Among the charged materials, the oldest ones are sequentially converted into volume based on the volume conversion coefficient in the solid-liquid mixed state, and the integrated value is “created by analyzing the situation inside the furnace in advance. From the time when the volume value of the solid-liquid mixed charge calculated based on the existing model was exceeded, this time, by performing volume conversion based on the volume conversion coefficient in the solid state and integrating, It is also characterized in that it enables stable blast furnace operation. "

[0009]

That is, according to the present invention, the actual volume value of the furnace interior charge at the time when charging of, for example, one charge to the blast furnace which continues to operate is completed is measured by a sounding level meter (the weight type furnace At the same time, the theoretical volume value of the charging material existing in the furnace at that time is calculated based on the level meter of the type that hangs down from the top to the upper surface of the furnace interior material and measures the position of the upper surface. The volume is calculated from the actual weighing results at the time of charging, and then the actual volume value and this theoretical volume value are compared, and when "actual volume value ≥ theoretical volume value", the charge is placed in the furnace interior most recently. Even if it is done, theoretically no charge is discharged outside the furnace. On the other hand, when "actual volume value <theoretical volume value", theoretically the oldest charge existing in the furnace (most furnace Tracking the contents inside the furnace, assuming that the charge located in the lower layer is discharged outside the furnace

According to this method, since the blast furnace charge tracking is performed in consideration of the volume of the charge existing in the actual furnace (based on the measured value of the sounding level meter, etc.), Unlike the "method of estimating the amount of residual iron and slag in the blast furnace from the" actual amount of slag and slag "and" calculated amount of slag and slag, " It is possible to control the amount of tapping and slag that matches the operation.

At this time, the logical volume value of the charge is calculated by calculating the theoretical volume of each charge by converting the bulk density (m ³ / ton) from the actual charging value (ton) of each charge. In this case, in this case, "bulk density conversion constant for a charge that has been melted in a furnace into a solid-liquid mixture" and "bulk density conversion for a charge that remains in a solid state". By setting two constants, "constant", and determining the volume of the solid-liquid mixed charge and the volume of the solid charge respectively, the theoretical volume value much better corresponding to the actual furnace situation can be obtained. You can

[0012] Specifically, first, from the "cohesive zone shape" obtained from the in-furnace condition model created by analyzing the in-furnace condition inside the blast furnace in advance, Calculate the calculated volume of the melt that is in a solid-liquid mixture. Next, determine the actual volume value of the furnace interior charge from the "furnace interior charge level measured by a sounding meter, etc.", and calculate the difference between this actual volume value and the calculated volume of the solid-liquid mixed charge. Determine the volume of the solid charge. On the other hand, by using the bulk density conversion constant, the theoretical volume when the solid-liquid mixed state is obtained in order from the oldest charge existing in the furnace. When the total amount is equal to or more than the liquid charge amount calculated based on the above model, the following charges (the theoretical volume in the case of solid-liquid mixed state until the final From the upper one of the chargers) to the solid charger
The theoretical volume is calculated by using the bulk density conversion constant for di, and the actual volume and the theoretical volume are compared. If such a second method is adopted, as described above, it is possible to manage the pig iron and slag that more accurately correspond to the actual furnace conditions.

The procedure for carrying out the present invention will be described below with reference to specific conditions set experimentally.

[Examples of Specific Procedures for Implementation] FIG. 3 is a flowchart relating to the overall procedure for carrying out the method of the present invention. In this example, the preconditions shown in (a) to (e) below were set. (a) For ease of verification, it is assumed that there is only one type of weighing setting charge in the furnace, and the actual weighing values of each charge are coke: 15ton, ore: 60ton. Assume a total of 75 tons. (b) The blast furnace body is assumed to be a cylinder with a radius of 7 m and a height of 30 m. (c) Bulk density conversion constant for solid charge is coke:
0.5ton / m ³ , ore: 2ton / m ³ , the bulk density conversion constant for solid-liquid mixed charge is coke: 0.5ton / m ³ ,
Ore: 6ton / m ³ (d) The volume of the solid-liquid mixture in the furnace interior, which is obtained from the “fused zone shape obtained from the model”, is 320 m ³ . (e) At this point, it is calculated that there are 8 charges of solid-liquid mixed charge and 42 charges of solid charge in the blast furnace as shown in FIG. To do.

Now, from this state, it is assumed that a new charge with a weighing result of coke: 25 ton, ore: 100 ton is charged, and the level of the charge in the furnace by the sounding level meter at that time is changed. It is assumed that it was located 18.6 m from the bottom of the furnace.

Then, the actual total volume of the charge in the furnace is "7 m × 7" from the measured value of the sounding level meter.
m × π × 18.6m≈2862m ³ ”. The calculated volume of the solid-liquid charge existing in the furnace is 300 m ^{3 when} calculated based on the model output, which is the actual volume of the solid-liquid charge. Therefore, based on these, the actual volume of the solid JoSo container is "2862m ³ - 300m ³ = 2562
m ³ ”. The state of the charging charge in the furnace at this point is schematically shown in FIG.

First, when mass balance calculation is performed on the solid charge, the total theoretical volume of the solid charge after charging the latest charge is calculated by weighing each charge. From actual results {15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 2 (ton /
m ³ )} × 42 + {25 (ton) /0.5 (ton / m ³ ) +100 (ton) /
2 (ton / m ³ )} = 2610m ³ .

On the other hand, since the actual volume of the solid charge at this time is 2562 m ³ as described above, “theoretical volume> actual volume” is established, and in terms of mass balance, the oldest charge of the solid charge is obtained.
Considering that the jelly has melted, the "oldest solid-state charge" is set as the first in tracking, and the theoretical volume is sequentially reduced to the next charge, the next charge, ....

At this time, first, when the theoretical volume of the "oldest solid state charge" is reduced, the theoretical volume of the solid-liquid mixed charge is multiplied by the above 1 charge. To do. Then, the volume of the solid-liquid mixed furnace interior charge is as follows. ^{320m 3 + {15 (ton)} / 0.5 (ton / m 3) + 60 (ton) / 6 (t
on / m ³ ) = 360m ³

Therefore, when the theoretical volume and the actual volume of the solid-liquid mixed charge are compared, "theoretical volume> actual volume" and "theoretical volume≤actual volume" is not established. In terms of balance, it is considered that the oldest solid-liquid mixed charge was discharged to the outside of the furnace, and in tracking, the theoretical volume is subtracted from the oldest solid-liquid mixed charge.

In this case, the oldest solid-liquid mixed charge is 1
Assuming that the charge is discharged, the theoretical volume is 360 m ³ − {15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 6 (t
on / m ³ ) = 320 m ³ , and “theoretical volume ≦ actual volume (300 m ³ )” has not been established yet. Therefore, if one more charge is discharged, the theoretical volume is 320 m ³ − {15 (ton) /0.5 (ton / m ³ ) +60 (ton) / 6 (t
on / m ³ ) = 280 m ³ and “theoretical volume ≦ actual volume” holds.

In other words, in this example of the method, in addition to the one existing in the furnace, a new charge whose coke weighing is 25 tons and ore is 100 tons is charged. Is the char that is being charged into the furnace until it is charged.
It is equivalent to about 1.6 times as much charge as that of coke (15 tons of coke and 60 tons of ore). Therefore, in this example, the charge (coke: 15 ton, ore: 60 ton mix) which is about 1.6 times the charge (coke: 15 ton, ore: 60 ton) charged in the furnace until the latest charge is charged. It is possible to understand that 2 charges were finally discharged to the outside of the reactor by charging a mixture of 25 tons of coke and 25 tons of ore.

As described above, the actual state cannot be grasped by the conventional simple tracking that "1 charge is always discharged to the outside of the furnace when charging is carried out", but it cannot be grasped in the actual furnace. With the method according to the present invention that performs tracking in consideration of the volume of the existing charging material (based on the measurement value of the sounding level meter), it is possible to grasp the actual situation accurately.

Therefore, by applying the method of the present invention to an actual furnace, not only during steady-state operation but also during unsteady operation such as reduced-scale operation, tracking of the charge accurately reflecting the in-reactor situation is performed. This enables accurate management of residual iron and residue even during unsteady operation.

[0024]

[Summary of Effects] As described above, according to the present invention, it is possible to more accurately estimate the amount of residual iron and the amount of residual slag in the blast furnace, which is performed for each tapping, and to perform proper and stable blast furnace operation. It is possible to bring about useful effects in industry.

[Brief description of drawings]

FIG. 1 is an explanatory diagram related to a scale-down operation of a blast furnace.

FIG. 2 is an explanatory diagram of a blast furnace operation example in which a charging amount and a discharging amount are different.

FIG. 3 is a flowchart showing the concept of charging tracking according to the present invention.

FIG. 4 is a schematic diagram illustrating an example of a situation of an initial blast furnace interior charging charge when implementing the present invention.

FIG. 5 is a schematic diagram for explaining an example of the situation of the charge for the blast furnace internal charge when charging one charge with an increased amount of charge.

Front Page Continuation (72) Inventor Tsuneji Masamori 1850 Minato, Wakayama, Wakayama Sumitomo Metal Industries, Ltd. Wakayama Works

Claims (2)

[Claims] 1. When charging a raw material into a blast furnace, a "charge level" immediately after the charging is measured every time the charging of the minimum unit for controlling the charging is completed, and the level is measured. The total volume (actual volume value) of the charge existing in the furnace is calculated from
After obtaining the theoretical volume value of the charge existing in the furnace at that time, the difference between the actual product volume value and the theoretical volume value (actual product volume value-theoretical volume value) was calculated, and this value was negative. In this case, the blast furnace operation is performed assuming that the charge existing in the furnace has been discharged out of the furnace in units of the smallest unit from the oldest one by the amount until the above value is positively converted. A method for tracking the contents of the blast furnace interior. 2. A minimum unit for management existing in the furnace is provided by providing a volume conversion coefficient in a solid-liquid mixed state and a volume conversion coefficient in a solid state in obtaining the theoretical volume of the charge existing in the furnace. Among the charged materials, the oldest ones are sequentially converted into the volume based on the volume conversion coefficient in the solid-liquid mixed state and integrated, and the integrated value is “created by analyzing the situation inside the furnace in advance. It is characterized by performing volume conversion based on the volume conversion coefficient in the solid state from the time when it exceeds the volume value of the solid-liquid mixed charge calculated based on the existing model. The method for tracking the interior contents of a blast furnace according to claim 1.